Fix Esp32 A0 definition, and ADC unit numbering (off-by-one)

Author: mikee47

Sming/Arch/Esp32/Core/adc.cpp

@@ -20,7 +20,7 @@ bool lookupAdc(uint16_t pin, AdcInfo& info)
 	for(unsigned adc = 0; adc < SOC_ADC_PERIPH_NUM; ++adc) {
 		for(unsigned ch = 0; ch < SOC_ADC_MAX_CHANNEL_NUM; ++ch) {
 			if(adc_channel_io_map[adc][ch] == pin) {
-				info.adc = adc_unit_t(adc + 1);
+				info.adc = adc_unit_t(adc);
 				info.channel = adc_channel_t(ch);
 				return true;
 			}

Sming/Arch/Esp32/Core/pins_arduino.h

@@ -12,6 +12,8 @@
 
 #pragma once
 
+#include <soc/adc_channel.h>
+
 #define EXTERNAL_NUM_INTERRUPTS 16
 #define NUM_DIGITAL_PINS 40
 #define NUM_ANALOG_INPUTS 16
@@ -20,7 +22,7 @@
 #define digitalPinToInterrupt(p) (((p) < 40) ? (p) : -1)
 #define digitalPinHasPWM(p) (p < 34)
 
-constexpr uint8_t A0{36};
+constexpr uint8_t A0 = ADC1_CHANNEL_0_GPIO_NUM;
 
 #define GPIO_REG_TYPE uint32_t